In the last two weeks, the plane flew roughly the same path 14 times, traversing the diagonal length of Ukraine to the Sea of Azov close to Crimea. But Thursday's route deviated slightly. The Boeing 777 went farther north than typical. It's unclear why.

A map shows the flight path Malaysia Airlines Flight 17 typically takes between Amsterdam and Kuala Lumpur, Malaysia, and the path it took when it went down in Ukraine July 17, 2014.

CBS News

Because of the conflict in the region, on April 3 the Federal Aviation Administration issued what's called a "notice to airman" prohibiting U.S. commercial flight operations in the airspace over Crimea and portions of the Black Sea and the Sea of Azov. But the notice did not cover the airspace where the Malaysia Airlines jet crashed.

The wreckage of Malaysia Airlines Flight 17 is seen in Ukraine July 17, 2014.

The Malaysian prime minister Thursday said the plane's route had been considered safe, but after the plane went down, other aircraft began to avoid the region.

The FAA has announced U.S. planes will also stay out of that airspace.

No airline in the world has gotten as much scrutiny over the last four months as Malaysia Airlines. Since March, along with the Malaysian government, it has been part of an international effort to find its missing jetliner, MH370, which disappeared from radar with 239 people on board. It was en route to Beijing from Kuala Lumpur and is now believed to have crashed in the southern Indian Ocean.

Typically investigators try to get to the scene as quickly as possible, but in this case because it's a war zone, it's unclear if and when a U.S. team of investigators will go to the crash site.